arch/x86/include/asm/fpu/xstate.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_X86_XSAVE_H
   3 #define __ASM_X86_XSAVE_H
   4
   5 #include <linux/uaccess.h>
   6 #include <linux/types.h>
   7
   8 #include <asm/processor.h>
   9 #include <asm/user.h>
  10
  11 /* Bit 63 of XCR0 is reserved for future expansion */
  12 #define XFEATURE_MASK_EXTEND    (~(XFEATURE_MASK_FPSSE | (1ULL << 63)))
  13
  14 #define XSTATE_CPUID            0x0000000d
  15
  16 #define FXSAVE_SIZE     512
  17
  18 #define XSAVE_HDR_SIZE      64
  19 #define XSAVE_HDR_OFFSET    FXSAVE_SIZE
  20
  21 #define XSAVE_YMM_SIZE      256
  22 #define XSAVE_YMM_OFFSET    (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET)
  23
  24 #define XSAVE_ALIGNMENT     64
  25
  26 /* All currently supported user features */
  27 #define XFEATURE_MASK_USER_SUPPORTED (XFEATURE_MASK_FP | \
  28                                       XFEATURE_MASK_SSE | \
  29                                       XFEATURE_MASK_YMM | \
  30                                       XFEATURE_MASK_OPMASK | \
  31                                       XFEATURE_MASK_ZMM_Hi256 | \
  32                                       XFEATURE_MASK_Hi16_ZMM     | \
  33                                       XFEATURE_MASK_PKRU | \
  34                                       XFEATURE_MASK_BNDREGS | \
  35                                       XFEATURE_MASK_BNDCSR)
  36
  37 /* All currently supported supervisor features */
  38 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
  39
  40 /*
  41  * A supervisor state component may not always contain valuable information,
  42  * and its size may be huge. Saving/restoring such supervisor state components
  43  * at each context switch can cause high CPU and space overhead, which should
  44  * be avoided. Such supervisor state components should only be saved/restored
  45  * on demand. The on-demand dynamic supervisor features are set in this mask.
  46  *
  47  * Unlike the existing supported supervisor features, a dynamic supervisor
  48  * feature does not allocate a buffer in task->fpu, and the corresponding
  49  * supervisor state component cannot be saved/restored at each context switch.
  50  *
  51  * To support a dynamic supervisor feature, a developer should follow the
  52  * dos and don'ts as below:
  53  * - Do dynamically allocate a buffer for the supervisor state component.
  54  * - Do manually invoke the XSAVES/XRSTORS instruction to save/restore the
  55  *   state component to/from the buffer.
  56  * - Don't set the bit corresponding to the dynamic supervisor feature in
  57  *   IA32_XSS at run time, since it has been set at boot time.
  58  */
  59 #define XFEATURE_MASK_DYNAMIC (XFEATURE_MASK_LBR)
  60
  61 /*
  62  * Unsupported supervisor features. When a supervisor feature in this mask is
  63  * supported in the future, move it to the supported supervisor feature mask.
  64  */
  65 #define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT)
  66
  67 /* All supervisor states including supported and unsupported states. */
  68 #define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
  69                                       XFEATURE_MASK_DYNAMIC | \
  70                                       XFEATURE_MASK_SUPERVISOR_UNSUPPORTED)
  71
  72 #ifdef CONFIG_X86_64
  73 #define REX_PREFIX      "0x48, "
  74 #else
  75 #define REX_PREFIX
  76 #endif
  77
  78 extern u64 xfeatures_mask_all;
  79
  80 static inline u64 xfeatures_mask_supervisor(void)
  81 {
  82         return xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_SUPPORTED;
  83 }
  84
  85 static inline u64 xfeatures_mask_user(void)
  86 {
  87         return xfeatures_mask_all & XFEATURE_MASK_USER_SUPPORTED;
  88 }
  89
  90 static inline u64 xfeatures_mask_dynamic(void)
  91 {
  92         if (!boot_cpu_has(X86_FEATURE_ARCH_LBR))
  93                 return XFEATURE_MASK_DYNAMIC & ~XFEATURE_MASK_LBR;
  94
  95         return XFEATURE_MASK_DYNAMIC;
  96 }
  97
  98 extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
  99
 100 extern void __init update_regset_xstate_info(unsigned int size,
 101                                              u64 xstate_mask);
 102
 103 void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
 104 int xfeature_size(int xfeature_nr);
 105 int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
 106 int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
 107 void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask);
 108 void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask);
 109
 110 enum xstate_copy_mode {
 111         XSTATE_COPY_FP,
 112         XSTATE_COPY_FX,
 113         XSTATE_COPY_XSAVE,
 114 };
 115
 116 struct membuf;
 117 void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
 118                              enum xstate_copy_mode mode);
 119
 120 #endif